You are running -release + errata patches, which may be equivalent to -stable, but is not exactly the same.

A -stable system may sometimes be identical to -release plus errata patches, and may sometimes include additional committed patches which are not broadly applicable or severe enough to be published as errata patches.

If -stable is desired or needed, the -stable system must be built by the local admin from the -stable branch of a CVS repository mirror, as articulated in the release(8) man page.

It can be confusing.

The OpenBSD Project publishes errata patches in source code form, and for some architectures also publishes these patches in binary form to be applied via the syspatch(8) tool. An admin can build and apply the patch from source, or, on some architectures, use the binary patch.

The Project does not distribute binary -stable systems, only -stable patches via developer commits to the OpenBSD source code CVS repository, which is then distributed to repository mirrors.

You are running -release + errata patches, which may be equivalent to -stable, but is not exactly the same.

A -stable system may sometimes be identical to -release plus errata patches, and may sometimes include additional committed patches which are not broadly applicable or severe enough to be published as errata patches.

If -stable is desired or needed, the -stable system must be built by the local admin from the -stable branch of a CVS repository mirror, as articulated in the release(8) man page.

It can be confusing.

The OpenBSD Project publishes errata patches in source code form, and for some architectures also publishes these patches in binary form to be applied via the syspatch(8) tool. An admin can build and apply the patch from source, or, on some architectures, use the binary patch.

The Project does not distribute binary -stable systems, only -stable patches via developer commits to the OpenBSD source code CVS repository, which is then distributed to repository mirrors.

ah ok, but how come my fresh install didn't say RELEASE either? i thought the IMAGE from the official site for creating the USB disk is supposed to be RELEASE?
for me, it still said GENERIC.MP#107 <--- just a different number than after i applied the patches with syspatch

The kernel build message for -release indicates the release number only, and does not include "-release" in the message. The -stable and -current flavors are additional indicators in the message, as defined in /usr/src/sys/conf/newvers.sh.

actually before i applied the patches, instead of showing RELEASE (pre syspatch), it was showing GENERIC.MP#107

My reading of this question is that it's a confusion between the terms GENERIC and -release. The two are essentially unrelated. GENERIC refers to a particular kernel configuration, i.e., what devices are compiled into the kernel and what parameters are used. This is unaffected by the OS branch, whether it's a -release, -stable, -current or -franken system, which refers to patch application and stage of development.